Why some standard specifications are harder to popularize than others?

The small things.

Case in point - using QoS with DDS. According to the specification, instead of

DDS::PublisherQos pub_qos (PUBLISHER_QOS_DEFAULT);

I should have written:

DDS::PublisherQos pub_qos;
dp->get_default_publisher_qos (pub_qos);

It's a small detail, but "what one doesn't know shouldn't hurt them" is a founding principle of any spec that people _want_ to use. In this instance my C++ knowledge misled me to make the "wrong" guess (according to DDS). However, DDS mapping allows _both_- they compile fine.

It's just the former simply doesn't work ...

(Thanks Adam, for setting me straight.)